It seems Facebook uses the Invision Power Board logo by default because that's what is set in the template's header.
I.e. via this code...
Perhaps it would be more desirable to either:
- Replace the IPB logo with the Eurobricks logo.
- Remove "image_src" line of code completely and then Facebook will parse the webpage looking for images to allow the user choose one.
- Get really clever and use the IPB for the Board Index and homepage, but let the user choose when the image they're posting a thread. After all, it may be preferable to the display a thumbnail of a MOC for example, rather than a logo. Assuming Facebook can extract the right image which is not always the case.